Two diets with different haemoglobin A1c and antiglycaemic medication effects despite similar weight loss in type 2 diabetes

We analysed participants with type 2 diabetes (n=46) within a larger weight loss trial (n=146) who were randomized to 48weeks of a low-carbohydrate diet (LCD; n=22) or a low-fat diet+orlistat (LFD+O; n=24). At baseline, mean body mass index (BMI) was 39.5kg/m(2) (s.d. 6.5) and haemoglobin A1c (HbA1c) 7.6% (s.d. 1.3). Although the interventions reduced BMI similarly (LCD -2.4kg/m(2); LFD+O -2.7kg/m(2), p=0.7), LCD led to a relative improvement in HbA1c: -0.7% in LCD versus +0.2% in LFD+O [difference -0.8%, 95% confidence interval (CI)=-1.6, -0.02; p=0.045]. LCD also led to a greater reduction in antiglycaemic medications using a novel medication effect score (MES) based on medication potency and total daily dose; 70.6% of LCD versus 30.4% LFD+O decreased their MES by 50% (p=0.01). Lowering dietary carbohydrate intake demonstrated benefits on glycaemic control beyond its weight loss effects, while at the same time lowering antiglycaemic medication requirements.